Protective effect of Wuzi Yanzong recipe on testicular DNA oxidative damage in natural ageing rats

Abstract

To study the protective effects of Wuzi Yanzong recipe on DNA oxidative damage of testis germ cells in natural ageing rats based on Nrf2/HO-1 signaling pathway and base excision repair (BER). In the study, 16-month-old SPF grade male SD rats were randomly divided into three groups, namely ageing model group, and low and high-dose Wuzi Yanzong recipe groups (WZ, 1, 4 g·kg⁻¹). In addition, 2-month-old SD rats were used as adult control group (10 rats in each group). The ageing model group and the adult control group were fed with normal diet for 4 months. WZ groups were given medicated feed for 4 months. After fasting for 12 hours, the rats were put to death. Then, the testes were immediately removed. The vitality of superoxide dismutase (SOD) and malondialdehyde (MDA) content in testis were detected by xanthine oxidase method and thiobarbituric acid (TBA) method. The levels of Nrf2 and 8-OHdG were detected by immunofluorescence. The protein expression levels of Nrf2, HO-1, NQO1, APE1, OGG1 and XRCC1 were detected by Western blot. Compared with the ageing model group, WZ significantly increased the SOD vitality and decreased MDA content of testis. In addition, immunofluorescence results showed that WZ significantly attenuated testicular DNA oxidative damage and improved antioxidant capacity. Such changes were accompanied by the down-regulation of DNA oxidative damage response protein 8-OHdG levels and the up-regulation of Nrf2 levels. Moreover, Western blot results showed that WZ significantly increased the protein expression levels of Nrf2, HO-1 and NQO1 of the testis germ cells, when compared with ageing model group. In parallel, the protein expression levels of APE1, OGG1 and XRCC1 were significantly decreased. In conclusion, WZ improves ageing-related DNA oxidative damage via Nrf2/HO-1 and BER pathways.